Microsoft Robotics products and services enable academic, hobbyist and commercial developers to easily create robotics applications across a wide variety of hardware.
Microsoft® Robotics Developer Studio 2008 Express Edition is a freely available .NET-based programming environment for building robotics applications. The Express Edition is fully functional version but has a feature set that better targets the non-professional developer and hobbyist.
Visit the MSDN Microsoft Robotics Developer Center where you can find details of the licensing agreement. You can download the application here: Download Microsoft Robotics Developer Studio 2008 Express Edition,
Check out the Microsoft Robotics Blog.
For more free software and online resources check out the BlogMS Resource Guide.